In part one of the two-hour season finale, Seattle Grace Hospital is hit with a crisis like no other in its history. Guest star Mandy Moore plays Mary, a patient of Bailey’s than Cristina and Meredith’s surgical skills are put to the ultimate test In part two of the two-hour season finale Grey’s Anatomy.

Here is short synopsis Grey’s Anatomy – Sanctuary:

The hospital is hit with an unprecedented crisis; Meredith and Cristina’s surgical skills are put to the test.